The use of touch-sensitive surfaces as input devices for computers and other electronic computing devices has increased significantly in recent years. Exemplary touch-sensitive surfaces include touch pads and touch screen displays. Such surfaces are widely used to manipulate user interface objects on a display.
Exemplary manipulations include adjusting the position and/or size of one or more user interface objects. Exemplary user interface objects include digital images, video, text, icons, and other graphics. A user may need to perform such manipulations on user interface objects in an image management application (e.g., Aperture or iPhoto from Apple Inc. of Cupertino, Calif.), a drawing application, a presentation application (e.g., Keynote from Apple Inc. of Cupertino, Calif.), a word processing application (e.g., Pages from Apple Inc. of Cupertino, Calif.), a website creation application (e.g., iWeb from Apple Inc. of Cupertino, Calif.), a disk authoring application (e.g., iDVD from Apple Inc. of Cupertino, Calif.), or a spreadsheet application (e.g., Numbers from Apple Inc. of Cupertino, Calif.).
But existing methods for performing these manipulations are cumbersome and inefficient. For example, existing keyboard-based methods require memorizing particular keys sequences for moving a user interface object by fine amounts (e.g., in one-pixel increments), which is tedious and creates a significant cognitive burden on a user. In addition, existing keyboard-based methods take longer than necessary, thereby wasting energy. This latter consideration is particularly important in battery-operated devices.